Add smoke tests for UOM conversions and enhance frontend UOM management

- Implemented smoke tests for UOM directionality, ensuring conversions are one-directional and correctly validated.
- Added tests for receiving and selling items in different UOMs, verifying correct quantity handling and error responses.
- Created a UOM conversions panel in the frontend to allow users to manage UOM conversions for items.
- Introduced hooks for allowed UOMs to optimize fetching and caching of UOM data for document line forms.
- Developed utility functions for consistent UOM formatting and conversion handling across the application.

Backend/ERPCore/Domain/Entities/BundleSaleLine.cs

@@ -11,9 +11,20 @@ public class BundleSaleLine
     public int ItemId { get; set; }
     public Item? Item { get; set; }
     public string Description { get; set; } = string.Empty;
+    /// <summary>Component quantity, in <see cref="UomId"/> — what the user entered.</summary>
     public decimal Qty { get; set; }
     public int UomId { get; set; }
     public Uom? Uom { get; set; }
+
+    /// <summary>
+    /// <see cref="Qty"/> restated in the item's base UOM, resolved once at save. Posting
+    /// consumes this. <see cref="Qty"/> and <see cref="UnitPrice"/> are always a matching
+    /// pair in <see cref="UomId"/>, so <see cref="LineTotal"/> stays value-correct.
+    /// </summary>
+    public decimal QtyBase { get; set; }
+
+    /// <summary>The factor used to derive <see cref="QtyBase"/>; 1 when the line is in base UOM.</summary>
+    public decimal ConversionFactor { get; set; } = 1m;
     public int WarehouseId { get; set; }
     public Warehouse? Warehouse { get; set; }
     public decimal UnitPrice { get; set; }

Backend/ERPCore/Domain/Entities/GrnLine.cs

@@ -34,8 +34,20 @@ public class GrnLine
     public int? BatchId { get; set; }
     public Batch? Batch { get; set; }
 
+    /// <summary>Quantity received, in <see cref="UomId"/> — what the user entered.</summary>
     public decimal Qty { get; set; }
 
+    /// <summary>
+    /// <see cref="Qty"/> restated in the item's base UOM, resolved once at line creation.
+    /// Confirm reads this snapshot rather than re-converting, so a conversion factor edited
+    /// between create and confirm cannot change what a saved GRN posts, and a later reversal
+    /// reproduces the original layer exactly.
+    /// </summary>
+    public decimal QtyBase { get; set; }
+
+    /// <summary>The factor used to derive <see cref="QtyBase"/>; 1 when the line is in base UOM.</summary>
+    public decimal ConversionFactor { get; set; } = 1m;
+
     /// <summary>Gross unit cost received at (entered, or PO price when omitted).</summary>
     public decimal UnitCost { get; set; }
 

Backend/ERPCore/Domain/Entities/PoLine.cs

@@ -21,8 +21,32 @@ public class PoLine
     public int WarehouseId { get; set; }
     public Warehouse? Warehouse { get; set; }
 
+    /// <summary>Quantity ordered, in <see cref="UomId"/>.</summary>
     public decimal Qty { get; set; }
     public decimal UnitPrice { get; set; }//
     public decimal Tax { get; set; }
+
+    /// <summary>
+    /// <see cref="Qty"/> restated in the item's base UOM, resolved once at line creation.
+    /// This — not <see cref="Qty"/> — is what open-quantity and close checks compare against,
+    /// because a GRN may legitimately receive against this line in a different UOM.
+    /// </summary>
+    public decimal QtyBase { get; set; }
+
+    /// <summary>The factor used to derive <see cref="QtyBase"/>; 1 when the line is in base UOM.</summary>
+    public decimal ConversionFactor { get; set; } = 1m;
+
+    /// <summary>
+    /// Accrues as GRNs confirm (FR-PROC-07), in <see cref="UomId"/>. <b>Denormalized for
+    /// display only</b> — it is derived by dividing <see cref="QtyReceivedBase"/> by the
+    /// factor, so it can drift. Never branch on it; use <see cref="QtyReceivedBase"/>.
+    /// </summary>
     public decimal QtyReceived { get; set; }
+
+    /// <summary>
+    /// Authoritative received-to-date in the item's base UOM. GRN confirm accrues here and
+    /// the PO close condition compares this against <see cref="QtyBase"/>, so receipts in a
+    /// UOM other than the PO's still add up correctly.
+    /// </summary>
+    public decimal QtyReceivedBase { get; set; }
 }

Backend/ERPCore/Domain/Entities/SalesInvoiceLine.cs

@@ -14,10 +14,24 @@ public class SalesInvoiceLine
 
     public string Description { get; set; } = string.Empty;
 
+    /// <summary>Quantity sold, in <see cref="UomId"/> — what the user entered and what prints.</summary>
     public decimal Qty { get; set; }
     public decimal FreeQty { get; set; }
     public int UomId { get; set; }
     public Uom? Uom { get; set; }
+
+    /// <summary>
+    /// <see cref="Qty"/> restated in the item's base UOM, resolved once at save. Posting
+    /// consumes stock against this snapshot — the FIFO engine is base-UOM only, so passing
+    /// the entered quantity would deplete the wrong amount whenever the line is not in base UOM.
+    /// </summary>
+    public decimal QtyBase { get; set; }
+
+    /// <summary><see cref="FreeQty"/> restated in the item's base UOM.</summary>
+    public decimal FreeQtyBase { get; set; }
+
+    /// <summary>The factor used to derive the base quantities; 1 when the line is in base UOM.</summary>
+    public decimal ConversionFactor { get; set; } = 1m;
     public int WarehouseId { get; set; }
     public Warehouse? Warehouse { get; set; }
 

Backend/ERPCore/Domain/Entities/SalesSlipLine.cs

@@ -14,10 +14,24 @@ public class SalesSlipLine
 
     public string Description { get; set; } = string.Empty;
 
+    /// <summary>Quantity sold, in <see cref="UomId"/> — what the user entered and what prints.</summary>
     public decimal Qty { get; set; }
     public decimal FreeQty { get; set; }
     public int UomId { get; set; }
     public Uom? Uom { get; set; }
+
+    /// <summary>
+    /// <see cref="Qty"/> restated in the item's base UOM, resolved once at save. Posting
+    /// consumes stock against this snapshot — the FIFO engine is base-UOM only, so passing
+    /// the entered quantity would deplete the wrong amount whenever the line is not in base UOM.
+    /// </summary>
+    public decimal QtyBase { get; set; }
+
+    /// <summary><see cref="FreeQty"/> restated in the item's base UOM.</summary>
+    public decimal FreeQtyBase { get; set; }
+
+    /// <summary>The factor used to derive the base quantities; 1 when the line is in base UOM.</summary>
+    public decimal ConversionFactor { get; set; } = 1m;
     public int WarehouseId { get; set; }
     public Warehouse? Warehouse { get; set; }